Fällung von Pentahalogenochromaten(III) aus wasserfreier Essigsäure

By adding alkali metal or ammonium acetate to solutions of Cr^III acetate in mixtures of acetic acid and acetyl halide, non-solvated alkali metal pentahalochromates(III), Cs₂(CrX₅), and acetic acid monosolvates of pentahalochromates(III) with nitrogen bases as a cation, i.e. (PyH)₂(CrX₅) · CH₃COOH, can be precipitated. Whilst the chlorochromate(III) ion shows a characteristic splitting of its ⁴A_2g—⁴T_2g absorption in acetic acid solution, which indicates C_4v symmetry, this splitting is not observed in all examined remission spectra of pentahalochromates(III) in the solid state. Their crystal structure should therefore be characterized by almost regular octahedral crystal fields of halogen around Cr³⁺ ions and probably by linked (CrX₆) units.     

Über Kupfer(I)-carboxylate und Chlorocuprate(I)

In mixtures of 7 vol. acetonitrile and 3 vol. acetic acid, solutions or suspensions of copper(II) acetate can be reduced with hydrazine hydrate to solutions of copper(I) acetate. In this way, purely white copper(I) acetate can be isolated. Other copper(I) carboxylates can be prepared by reduction of copper(II) carboxylates or by reaction of solid carboxylic acids with copper(I) acetate. By adding acetyl chloride to solutions of copper(I) acetate in acetonitrile/acetic acid mixtures, solutions of chlorocuprates(I) are formed. From these, highly pure copper(I) chloride can be obtained. By adding alkali acetate or tetramethyl ammonium chloride to solutions of chlorocuprates(I), the pure compounds Cs₃[Cu₂Cl₅], Rb₂[CuCl₃] and NMe₄[Cu₂Cl₃] were obtained.     

Metall-Koordinationsverbindungen aus Essigsäure. I Chlorometallate(III) des Eisens,Chroms und Vanadiums

Metal Coordination Compounds Prepared in Acetic Acid. I. Chlorometalates(III) of Iron, Chromium, and Vanadium Ternary chloride-hydrates A₂MCl₅ · H₂O (A = Cs, Rb, (K)) can be precipitated with HCl from solutions of MCl₃ · 6 H₂O, (M = Fe, Cr, V) and alkali metal acetates in acetic acid. Under special conditions also compounds of the composition Cs₃MCl₆ · H₂O can be obtained. After dehydration of the solutions with acetyl chloride, anhydrous compounds are formed: Cs₃Fe₂Cl₉; A₃CrCl₆ and A₃Cr₂Cl₉ with A = Cs, Rb; Cs₃VCl₆ and Cs₃V₂Cl₉. V^III is partially oxidized to V^IV by an excess of acetyl chloride. Compounds A₂VCl₆ with A = Cs, Rb can be obtained more conveniently by the reaction of VOCl₂ · H₂O in acetic acid with acetyl chloride. The lattice parameters of some compounds were determined from powder patterns in analogy to known structure families.     

Crystal and molecular structure of N-methyl-bis(2-hydroxyethyl)ammonium (4-chlorphenylsulfonyl)acetate

By X-ray diffraction the crystal and molecular structure of N-methyl-bis(2-hydroxyethyl)ammonium (4-chlorphenylsulfonyl)acetate 4-ClC₆H₄SO₂CH₂COO^?·CH₃N⁺H(CH₂CH₂OH)₂ synthesized by the interaction of (4-chlorphenylsulfonyl)acetic acid with N-methyl-bis(2-hydroxyethyl)amine is studied.     

An investigation of the electron density of a Jahn–Teller‐distorted CrII cation: the crystal structure and charge density of hexakis(acetonitrile‐κN)chromium(II) bis(tetraphenylborate) acetonitrile disolvate

In the crystal structure of the title homoleptic Cr^II complex, [Cr(CH₃CN)₆](C₂₄H₂₀B)₂·CH₃CN, the [Cr(CH₃CN)₆]²⁺ cation is a high‐spin d⁴ complex with strong static, rather than dynamic, Jahn–Teller distortion. The electron density of the cation was determined by single‐crystal X‐ray refinements using aspherical structure factors from wavefunction calculations. The detailed picture of the electronic density allowed us to assess the extent and directionality of the Jahn–Teller distortion of the Cr^II cation away from idealized octahedral symmetry. The topological analysis of the aspherical d‐electron density about the Cr^II cation showed that there are significant valence charge concentrations along the axial Cr—N axes. Likewise, there were significant valence charge depletions about the Cr^II cation along the equatorial Cr—N bonds. These charge concentrations are in accordance with a Jahn–Teller‐distorted six‐coordinate complex.     

Preparation of non-valence compounds of zinc(II) with 1,2- and 1,4-benzenedicarboxylic acids via self-assembly

Nanostructured non-valence compounds based on coordination compounds of zinc(II) with phthalic and terephthalic acids have been prepared. The purity and composition of prepared compounds have been elucidated from X-ray diffraction analysis, IR spectroscopy, elemental analysis, and thermogravimetry studies; thermal decomposition of the non-valence compounds has been studied as well. The prepared self-assembled compounds are co-precipitated with one water molecule and 1.5 acetic acid molecules per unit of the dicarboxylic acid: [Zn₄(OH)₆·o-C₆H₄(COO)₂]·H₂O·1.5CH₃COOH and [Zn₄(OH)₆·p-C₆H₄(COO)₂]·H₂O· 1.5CH₃COOH.     

Construction of Mononuclear Copper(II) and Trinuclear Cobalt(II) Complexes Based on Asymmetric Salamo‐Type Ligands

Mononuclear copper(II) and trinuclear cobalt(II) complexes, namely [Cu(L¹)]₂ · CH₂Cl₂ and [{Co(L²)(EtOH)}₂Co(H₂O)] · EtOH {H₂L¹ = 4,6‐dichloro‐6′‐methyoxy‐2,2′‐[1,1′‐(ethylenedioxydinitrilo)dimethylidyne]diphenol and H₃L² = 6‐ethyoxy‐6′‐hydroxy‐2,2′‐[1,1′‐(ethylenedioxydinitrilo)dimethylidyne]diphenol}, were synthesized and characterized by elemental analyses, IR and UV/Vis spectroscopy, and single‐crystal X‐ray diffraction. In the Cu^II complex, the Cu^II atom is four‐coordinate, with a N₂O₂ coordination sphere, and has a slightly distorted square‐planar arrangement. Interestingly, the obtained trinuclear Co^II complex is different from the common reported 2:3 (L:Co^II) salamo‐type Co^II complexes. Infinite 2D layer supramolecular structures are formed via abundant intermolecular hydrogen bonding and π ··· π stacking interactions in the Cu^II and Co^II complexes.     

Über die Umsetzung von Mangan(III) mit Acetylchlorid und die Fällung von Chloromanganaten in Essigsäure

In accordance with spectrophotometric measurements, manganese(III) acetate dihydrate reacts with dilute solutions of acetyl chloride in acetic acid through a 1:1 complex to a red-violet 1:4 compound which is unstable due to the oxidation potential of Mn^III ions. The action of potassium acetate on solutions of Mn^III in acetic acid in presence of a large excess of acetyl chloride leads to a dismutation of managanese(III) and initial precipitation of potassium chloromanganate(IV), K₂MnCl₆. During the reaction of potassium acetate with solutions of manganese(II)/acetic acid/acetyl chloride, under particular conditions, first nonsolvated potassium trichloromanganate(II), KMnCl₃, is formed, which transforms during further addition of potassium ions to tetrapotassium hexachloromanganate(II), K₄MnCl₆.     

Monomeric dioxouranium(VI), chromium(III), cobalt(II), nickel(II) and copper(II) complexes with primary cellulose acetate (PCA)

Monomeric UO ₂ ²⁺ , Cr^III, CO^II, Ni^II and Cu^II complexes with primary cellulose acetate (PCA) have been prepared and characterized. Infrared,¹H NMR, UV/visible spectroscopy, elemental analysis, therniogravimetry, conductance and magnetic measurements were used to assign the mode of coordination in the isolated species. The investigation revealed that PCA exhibits octahedral coordination with Cr^III, Co^II, Ni^II and a square planar form with Cu^II whereas the UO₂ moiety is virtually linear. PCA acts as a neutral bidentate chelating agent via the two oxygen atoms of the vicinal ester groups in the secondary positions forming a five-membered chelate ring. A comparative study between chelates of PCA and those previously prepared with secondary cellulose acetate (SCA) has been undertaken.     

Mössbauer study on solid state photolysis of alkali tris(malonato)ferrates(III)

Solid state photolysis of alkali tris(malonato)ferrates(III), i.e., M₃[Fe(CH₂C₂O₄)₃]xH₂O (M=Li, Na, K, NH₄) has been studied employing Mössbauer, infrared and reflectance spectroscopic techniques. The complexes were irradiated for 300 hours using a medium pressure mercury vapour lamp of 250 W, Photodecomposition led to the formation of an iron(II) intermediate, M₂[Fe^II(CH₂C₂O₄)₂(H₂O)₂] (M=Li, Na, K) which on prolonged standing in air oxidized to M[Fe^III(CH₂C₂O₄)₂(H₂O)₂]. However, in case of ammonium complex, Fe^IICH₂C₂O₄·2H₂O once formed remained stable. The extent of photoreduction showed the sequence: NH₄, K>Li>Na. The results have been compared with those of alkali tris (oxalato) ferrates(III).     

Copper(II), Cobalt(II), and Nickel(II) Complexes of two Novel Pyridine‐derived Macrocyclic Ligands bearing o‐ and pNitrobenzyl Pendant Groups

The pendant‐armed ligands L¹ and L² were synthesized by N‐alkylation of the four secondary amine groups of the macrocyclic precursor L using o‐nitrobenzylbromide (L¹) and p‐nitrobenzylbromide (L²). Nitrates and perchlorates of Cu^II, Ni^II and Co^II were used to synthesize the metal complexes of both ligands and the complexes were characterized by microanalysis, MS‐FAB, conductivity measurements, IR and UV‐Vis spectroscopy and magnetic studies. The crystal structures of L¹, [CuL¹](ClO₄)₂·CH₃CN·H₂O, [CuL²](ClO₄)₂·6CH₃CN, [CuL²][Cu(NO₃)₄]·5CH₃CN·0.5CH₃OH and [NiL²](ClO₄)₂·3CH₃CN·H₂O were determined by single crystal X‐ray crystallography. These structural analysis reveal the free ligand L¹, three mononuclear endomacrocyclic complexes {[CuL¹](ClO₄)₂·CH₃CN·H₂O, [CuL²](ClO₄)₂·6CH₃CN and [NiL²](ClO₄)₂·3CH₃CN·H₂O} and one binuclear complex {[CuL²][Cu(NO₃)₄]·5CH₃CN·0.5CH₃OH} in which one of the metals is in the macrocyclic framework and the other metal is outside the ligand cavity and coordinated to four nitrate ions.     

Kronenthioetherkomplexe des Blei(II), Zink(II) und Cadmium (II) und Cadmium(II). Die Kristallstrukturen von [PbL2(ClO4)2] und [ZnL2](ClO4)2 · CH3CN (L = 1,4,7 - Trithiacyclononan)

Crown Thioether Complexes of Lead (II), Zinc(II), and Cadmium (II). Crystal Structures of [PbL₂(ClO₄)₂] and [ZnL₂](ClO₄)₂ · CH₃CN (L = 1,4,7 - Trithiacyclononane) The reaction of 1,4,7-trithiacyclononane (L) with the perchlorate salts of lead(II) and zinc(II) in CH₃CN (2:1) affords colorless crystals of [PbL₂(ClO₄)₂] and [ZnL₂](ClO₄)₂ · CH₃CN, respectively, The crystal structures have been determined. The Pb^II centre is coordinated to six sulfur atoms (the average distance Pb? S is 3.076 Å) and two oxygen atoms, one of each ClO₄^? anion (monodentate ClO₄^?). A distorted square antiprismatic polyhedron is thus generated. In [ZnL₂](ClO₄)₂ · CH₃CN the zinc(II) centre is octahedrally surrounded by six sulphur atoms (average distance Zn? S = 2.494 Å); the ClO₄^? anions are not coordinated. For[CdL₂](ClO₄)₂ · H₂O an analogous structure is proposed.     

Extraction of Lanthanide Nitrates in Multicomponent Aqueous-Organic Two-Phase Systems with D2EHPA

Lanthanum nitrate distribution in three-component aqueous-organic systems with D2EHPA from acetate or acetic acid–acetate solutions has been studied, it has been shown that variation in sodium acetate concentration or composition of CH₃COONa–CH₃COOH mixture can affect metal distribution ratios. It has been found that extraction in three-component mixture of 1: 1: 1 composition (aqueous solution Ln(NO₃)₃ + CH₃COONa + CH₃COOH–D2EHPA in hexane–isopropyl alcohol) can provide lanthanide separation, which is dependent on the ratio of sodium acetate and acetic acid in aqueous phase and on D2EHPA concentration in organic phase. Lanthanide–lanthanum separation factors have been calculated for the extraction of lanthanide nitrates from acetic acid–acetate solutions.     

Synthesis,Characterization and Structure of Bis‐ and Tetrakis‐Aziridine‐Nickel(II) and Copper(II) Complexes

The synthesis and characterization of mononuclear tetrakis‐aziridine nickel(II ) and copper(II ) complexes as well as of a dinuclear bis‐aziridine copper(II ) complex are described. The reactions of anhydrous MCl₂ (M = Ni^II, Cu^II) with aziridine (= az = C₂H₄NH, C₂H₃MeNH, CH₂CMe₂NH) in CH₂Cl₂ at room temperature in a 1:5 and 1:2 molar ratio, respectively, afforded the tetrakis‐aziridine complexes [M(az)₄Cl₂] (M = Ni, Cu) or the dimeric bis‐aziridine complex [Cu(az)₂Cl₂]₂. After purification, all of the complexes were fully characterized. The single crystal structure analysis revealed two different coordination modes. Whereas both nickel(II ) complexes can be classified as showing an elongated octahedral structure, copper(II ) complexes show either an elongated octahedral or a square pyramidal arrangement forming dimers with chlorido bridges in axial positions. Furthermore, the results of magnetic measurements of the nickel(II ) and copper(II ) compounds are presented.     

Bildung und Fällung von Bromocadmaten in Essigsäure als Lösungsmittel

Cadmium bromide reacts in anhydrous acetic acid solutions with acetyl bromide to form bromocadmates which can be precipitated as ammonium salts. By conductometric control and X-ray diffraction the phases (NH₄)(CdBr₃), (NH₄)₂ (CdBr₄) and (NH₄)₄(CdBr₆) have been found which decompose on heating as ordinary double salts to ammonium bromide and cadmium bromide.     

Synthesis and structural characterization of new trinuclear cobalt(II) and nickel(II) complexes possessing five- and six-coordinated geometry

Tri-nuclear cobalt and nickel complexes ([(CoL)₂(OAc)₂Co]?·?THF (I) and [(NiL)₂(OAc)₂(THF)₂Ni]?·?THF (II)) have been synthesized by reaction of a new Salen-type bisoxime chelating ligand of 2,2′-[ethylenedioxybis(nitrilomethylidyne)]dinaphthol(H₂L) with cobalt(II) acetate tetrahydrate or nickel(II) acetate tetrahydrate, respectively. Complexes I and II were characterized by elemental analyses, IR, TG-DTA and ¹H-NMR etc. The X-ray crystal structures of I and II reveal that two acetate ions coordinate to three cobalt or nickel ions through M–O–C–O–M (M?=?Co or Ni) bridges and four μ-naphthoxo oxygen atoms from two [ML] units also coordinate to cobalt(II) or nickel(II). Complex I has two distorted square-pyramidal coordination spheres and an octahedral geometry around Co1. In complex II all three nickel ions are six-coordinate.     

Mn3(OAc)6·CH3CN: a porous dehydrated manganese(II) acetate

The crystal structure of a new form of dehydrated manganese(II) acetate, poly[[hexa‐μ₃‐acetato‐trimanganese(II)] acetonitrile solvate], {[Mn₃(CH₃COO)₆]·CH₃CN}_n, (I), reveals a three‐dimensional polymeric structure based on an {Mn₃} trimer. The {Mn₃} asymmetric unit contains three crystallographically independent Mn positions, comprising a seven‐coordinate center sharing a mirror plane with a six‐coordinate center, and another six‐coordinate atom located on an inversion center. Two of the four crystallographically independent acetate (OAc) ligands, as well as the acetonitrile solvent molecule, are also located on the mirror plane. The Mn atoms are connected by a mixture of Mn—O—Mn and Mn—OCO—Mn bridging modes, giving rise to face‐ and corner‐sharing interactions between manganese polyhedra within the trimers, and edge‐ and corner‐sharing connections between the trimers. The network contains substantial pores which are tightly filled by crystallographically located acetonitrile molecules. This structure represents the first porous structurally characterized phase of anhydrous manganese(II) acetate and as such it is compared with the closely related densely packed anhydrous manganese(II) acetate phase, solvent‐free β‐Mn(OAc)₂.     

Synthesis and Crystal Structure of Rubidium Lanthanum Tetraacetate,RbLa(CH3COO)4

The anhydrous rubidium tetraacetato lanthanate, RbLa(CH₃COO)₄, is obtained together with Rb₂La(CH₃COO)₅(H₂O) as colourless single crystals from a 1 : 2 mixture of Rb₂CO₃ and La(CH₃COO) · 1.5 H₂O in acetic acid by slow evaporation. The crystal structure [orthorhombic, Pnnm, Z = 2, a = 1242.0(3), b = 1650.1(4), c = 698.0(4) pm, R = 0.028, R_w = 0.071] contains La³⁺ nine coordinate by oxygen atoms of six acetate ligands. The polyhedra are connected to dimers and further to double chains running parallel to [001]. These [La(CH₃COO)₄]^– double chains are surrounded by four like double chains and connected by Rb⁺ ions that are seven coordinate by oxygen atoms.     

Synthesis,structural and spectroscopic characterization of a new cadmium(II) complex containing imidazole (Im) as ligand, [Cd(Im)6](ClO4)2

Reaction between the 1,1′-carbonyldiimidazole ligand and mixtures of cadmium(II) acetate with sodium perchlorate provided the unusual crystalline material [Cd(Im)₆](ClO₄)_2, (Im?=?imidazole). This new Cd^II complex, has been characterized by elemental analysis, IR-, ¹H NMR-, ¹³C NMR and ¹¹³Cd NMR spectroscopy. The coordination number in this complex is six, CdN₆ and coordination environment around the Cd(II) may be described as distorted octahedral with a D_2h point group. There are both edge-to-face π–π stacking and C–H(Im)?···?π interactions between aromatic “Im” rings belonging to adjacent chains in this network.     

Adducts of tetraphenylstibium nitrate with nitric acid and of tetraphenylstibium acetate with acetic acid: Syntheses and structures

The reactions of tetraphenylstibium nitrate with nitric acid and of tetraphenylstibium acetate with acetic acid yield adducts Ph₄SbONO₂ · HNO₃ (I) and Ph₄SbOC(O)CH₃ · CHH₃COOH (II). According to X-ray diffraction data, the antimony atom in [Ph₄Sb]⁺[O₂N-O···H···O-NO₂]^? has a tetrahedral coordination. The CSbC bond angles and Sb-C bond lengths vary within 108.04(6)°–109.75(4)° and 2.096(1)–2.098(1) Å, respectively. The anion includes the intermolecular hydrogen bond O(1)–H(1)···O(1)″: the O(1)-H(1), H(1)···O(1)″, and O(1)···O(1)″ distances are 0.91(4), 1.56(4), and 2.460(2) Å, respectively; and the OHO angle is 169(5)°. The nitrate groups are usually planar. Complex II also contains the intermolecular hydrogen bond with the following parameters: O(3)-H(3), 0.92 Å; H(3)···O(2), 1.68 Å; and O(3)···O(2) 2.594 Å; the O(2)H(3)O(3) angle is 172.1°. This H-bond noticeable changes the coordination polyhedron of the antimony atom compared to that in tetraphenylstibium acetate.